This is a response to a NIDA RFA for the establishment of a Neuroscience Network. This proposal contains a series of highly interdigitated projects, connected both scientifically and technically. The major theme running through all four projects is the action of neurotrophic factors and cytokines in neural systems relevant to drug abuse. A second major theme running through three of the four projects is modulation of mesolimbic dopamine systems by neurotransmitters and trophic factors. A third theme binding two of the projects closely together is the study of cholinergic-dopaminergic interactions. The Network involves entirely new project from two labs already involved in drug abuse research and recruits the laboratories of two well established neuroscientists to drug abuse research for the first time. A major connection of all the investigators is their commitment to the use of molecular and cellular tools in the service of understanding brain and behavior. The investigators, who comprise a highly collegial group, well known to each other, are particularly enthusiastic about the communications core which will facilitate their work together. This RFA has provided an opportunity for the group to develop synergistic interactions across physical distance that will speed their investigations of fundamental processes in the nervous system relevant to the actions of drugs of abuse.